From the sayings of StSyncletica about Prayer

“There is a grief that is useful, and there is a grief that is destructive. The first sort consists in weeping over one’s own faults and weeping over the weakness of one’s neighbours, in order not to lose one’s purpose, and attach oneself to the perfect good. But there is also a grief that comes from the enemy, full of mockery. This spirit must be cast out, mainly by prayer and psalmody.”